500 MHz SAW RESONATOR-OSCILLATOR

SAW resonator-oscillator are characterized by its high fundamental frequency,low phase noise,reliable performance,simple,light weight,compact volume,and the resistance against the mechanical vibration.It has begun to be used as one of valuable device in practice.The 500 MHz one-port SAW groove resonator made in our laboratory,for which the unloading quality factor Q_u>20,000,and the motional resistance R₁=20-30 Ω,has been used as a frequency controlled element to construct an oscillator.Its short term stability measured in 0.001 second is 4.2×10^-10,in 0.01 second is 2.8×10^-10,in 0.1 second is 2.5×10^-10 and in 1 second is 5.5×10^-10,the single sideband phase noise for 1 kHz offset from the carrier is 108 dBC.When not being closed in ovens,for the ambient temperature range from-30℃ to+60℃ the total fractinal change on frequency of oscillator is 1.1×10^-4,and average value is 1.2×10^-6.At room temperature,the average frequency,fluctuation is 2.7×10^-6/d.